Most existing computer systems are built around a single high-speed common bus. As semiconductor technology advances, faster digital devices can be constructed. This allows the devices sharing a bus to recognize and respond to briefer, higher-frequency bus signals. Unfortunately, this improvement also makes each bus device capable of consuming a greater portion of the total bus bandwidth. Any gains obtained through process improvements can quickly be offset by adding a small number of high-speed devices to the bus.
One solution is to boost the signal bandwidth of the bus by, for example, using fiber optics as a communications channel. However, a single, large bandwidth bus introduces additional problems in handling the bus in the physical environment of the typical computer.
Another way to circumvent the bandwidth limitations of a common bus is to provide a distributed communication scheme. In this approach, the components of a system are interconnected by multiple local buses. Both the nature and number of local buses can be varied to match the communications needs of a particular system.
A hypercube-based system provides multiple paths between masters and slaves. These paths are not what one thinks of as busses. Rather they are communication links between nodes which allow traffic to communicate with the attached nodes, or to pass through the connection to more distant nodes. The traffic consists of messages which are interpreted by the slave, as against specific memory accesses such as are used on busses.
A mesh multicomputer system is similar in function to a hypercube except that it generally takes the form of a two-dimensional array with, therefore, four communication ports at each node.
A multicomputer is a type of parallel processor that consists of an ensemble of computing nodes, each of which is a relatively complete and self-sufficient computing environment. The relative self-sufficiency of multicomputer nodes differentiates multicomputers from multiprocessors.
The object of the invention is to provide, for a complex multicomputer, a scalable, high performance multicomputer communication system in which multiple, direct memory accesses can occur simultaneously. Another object is to provide for a large number of computing nodes. Still another object is to provide a high performance multicomputer with reliable standard functional modules.